Communicating Applications Spec - Get hardware status

        Entry:
          AX = CB12h
          DS:DX -> 128-byte status buffer
        Return:
          AX = 0000h successful
               buffer filled with hardware-dependent status information
             < 0   error code (see AX=CB01h)

        Format of status buffer for Intel Connection CoProcessor:

        Offset  Size    Description
         00h    BYTE    bit flags
                        bit 7: hardware busy sending or receiving
                        bit 6: last page of data
                        bit 5: no data on current page
                        bit 4: retransmit request for current page being
                               transmitted
                        bit 3: NSF mode active
                        bits 2-0: reserved
         01h    BYTE    number of kilobytes of free buffer space
         02h    BYTE    page buffer status
                        bit 7: Connection CoProcessor has documents to send
                        bits 6-0: number of pages in buffer
         03h    BYTE    number of retries left for dialing number
         04h    BYTE    page number to retransmit
         05h    BYTE    communications status
                        bit 7: originating call
                        bit 6: FAX message to be sent
                        bit 5: on line
                        bit 4: ring detected and receive enabled
                        bit 3: buffer dumped on receive
                        bits 2-0: hardware sequence state
                                000 idle
                                001 dial
                                010 answer
                                011 transmit
                                100 receive
                                101 pre-message
                                110 post-message
                                111 disconnect
         06h    BYTE    baud rate
                        bit 7: reserved
                        bits 6-4: baud rate
                                000 = 300 baud (SDLC mode)
                                100 = 2400 baud
                                101 = 4800 baud
                                110 = 7200 baud
                                111 = 9600 baud
                        bits 3-0: reserved, should be 0110
         07h  3 BYTEs   reserved
         0Ah    BYTE    hardware status
                        bit 7: modem option installed
                        bit 6: Connection CoProcessor has control of DAA (not latched)
                        bit 5: on line (not latched)
                        bit 4: ring detected (not latched)
                        bit 3: data in command buffer (not latched)
                        bit 2: set if using DMA channel 1, clear if using DMA channel 3
                        bit 1: line length compensation bit 1 set (not latched)
                        bit 0: line length compensation bit 0 set (not latched)
         0Bh    BYTE    switch states
                        bit 7: reserved
                        bit 6: unused
                        bit 5: spare switch open
                        bit 4: FAX ADR1 switch open
                        bit 3: FAX ADR0 switch open
                        bit 2: alternate interrupt switch open
                        bit 1: COM SEL 1 switch open
                        bit 0: COM SEL 0 switch open
         0Ch    BYTE    bit flags
                        bit 7: reserved
                        bit 6: auxiliary relay forced ON
                        bit 5: modem select relay forced ON
                        bit 4: offhook relay forced ON
                        bit 3: 9600 bps enabled
                        bit 2: 7200 bps enabled
                        bit 1: 4800 bps enabled
                        bit 0: 2400 bps enabled
         0Dh    BYTE    reserved
         0Eh    WORD    error count
         10h    DWORD   size of nonstandard format (NSF) file in bytes
         14h 10 BYTEs   reserved
         1Eh 21 BYTEs   ASCIZ CCITT identification
         33h 77 BYTEs   reserved